Lady Banksia Yellow Rose - Knowledgebase Question

I have a Lady Banks Yellow Rose that is about 16 years old. It seems to be very weak - it was once vigorous and healthy, now it's thin and appears to be dying (for the last two years). It does not have a mold problem, nor do I see any particular insects or markings. Is it just reaching the end of it's life span (what is the life span??) or could there be another problem?
Thanks!

Lady Banksia roses will live for many generations so I don't think it has reached old age yet. It it is not as vigorous as it once was, think about what may have changed over the past few years. Less sunlight, less fertilizer, more competition for root space? If none of these seem to fit, how about pruning? Lady Banks flowers on new growth so it depends upon annual pruning for ultimate growth and flower production. Pruning her back should encourage healthy new growth. You should be able to safely prune it back by one third, removing some of the oldest canes completely and shortening the others. Or, if it's really in decline, you can chop it down just above ground level and allow new sprouts to become your new plant. I'd reserve this major pruning as a last ditch effort, though. Best wishes with your rose!